A series of Ho3+Yb3+-F(-)tri-doped TiO2 nanoparticles (abbreviated as UP-F-TiO2 NPs) were prepared using a hydrosol-hydrothermal method, and their phase structure, morphology and luminescent properties were investigated. These nanoparticles were utilized to prepare a photoanode of dye-sensitized solar cells (DSSCs). Based on the up-conversion spectra of UP-F-TiO2 NPs, an up conversion mechanism is proposed. The results indicate that the UP-F-TiO2 NPs were a mixture of anatase and rutile nanoparticles, and the mass fraction of the anatase phase first increases and then decreases with increasing incorporation of F-ions into UC-F-TiO2 NPs, while the uti-doped TiO2 nanoparticles are in the rutile phase. The average sizes of the UP-F-TiO2 NPs are estimated to be 10 nm. The HRTEM shows clear lattice fringes with spacings of 0347 rim and 0.323 nm that correspond to the d spacings of the (101) facets in anatase TiO2 and the (110) facets in rutile TiO2, respectively. Under the excitation of 980 nm NIR light, the UP-F-TiO2 NPs exhibit a stronger emission band centered at 543 nm and two relatively weaker bands located at 667 nm and 751 nm. The DSSC assembled with a bilayer-structured UP-F-TiO2 NP photoanode has a 35.2% enhancement in conversion efficiency compared with DSSCs assembled with undoped TiO2 photoanodes. (C) 2016 Elsevier Ltd. All rights reserved.